ypes and Symptoms
There are three types of anthrax. The most common case of anthrax in humans is cutaneous anthrax . This
form of anthrax is acquired through the skin, from a cut or abrasion. The anthrax spores then enter the wound
from the soil or an infected animal body. A swollen, itchy bump will form on an area of the skin and, over a
period of few days of swelling, a black scab will form in the center of the bump. The name anthracis is derivative
of the Greek word for coal because of this black scab that it leaves on the skin. In extreme cases the bloodstream
is invaded and the disease becomes, most likely, fatal.
Another form of the disease is gastrointestinal anthrax. This form of anthrax is similar to cutaneous anthrax
in the way that it probably infects the body through an already existing intestinal lesion. It occurs when a person
ingests unproperly cooked meat of an animal that was infected or drinks contaminated water. The bacteria spread from the lesion to the lymphatic system. The symptoms are fever, severe stomach pains, nausea, vomiting, sore
throat, tongue sores, and bloody diarrhea. Although rare, this form of anthrax has an enormously high mortality
rate.
Anthrax, a highly infectious and fatal disease of mammals and humans, is caused by a relatively large spore-forming rectangular shaped bacterium called Bacillus anthracis.
Anthrax occurs on all the continents, causes acute mortality in ruminants and is a zoonosis. The bacteria produce extremely potent toxins which are responsible for the ill effects, causing a high mortality rate. While most mammals are susceptible, anthrax is typically a disease of ruminants and humans.
It does not typically spread from animal to animal nor from person to person. The bacteria produce spores on contact with oxygen.
Clinical Signs
Sudden death (often within 2 or 3 hours of being apparently normal) is by far the most common sign;
Very occasionally some animals may show trembling, a high temperature, difficulty breathing, collapse and convulsions before death. This usually occurs over a period of 24 hours;
After death blood may not clot, resulting in a small amount of bloody discharge from the nose, mouth and other openings/
Diagnosis
On the clinical signs described above;
Rod-shaped bacteria surrounded by a capsule are visible in blood smears made from surface blood vessels
Post-mortem examinations should not be undertaken on suspected anthrax cases (including any cow that has died suddenly for no apparent reason) until a blood smear has proved negative);
If a carcass is opened accidentally, the spleen is usually swollen and there is bloodstained fluid in all body cavities.
Treatment
Due to the rapidity of the disease treatment is seldom possible, although high doses of penicillin have been effective in the later stages of some outbreaks.
Prevention
Infection is usually acquired through the ingestion of contaminated soil, fodder or compound feed. Anthrax spores in the soil are very resistant and can cause disease when ingested even years after an outbreak. The spores are brought to the surface by wet weather, or by deep tilling, and when ingested or inhaled by ruminants the disease reappears.
Where an outbreak has occurred, carcases must be disposed of properly, the carcase should not be open (exposure to oxygen will allow the bacteria to form spores) and premises should be quarantined until all susceptible animals are vaccinated.
Vaccination in endemic areas is very important. Although vaccination will prevent outbreaks veterinary services sometimes fail to vaccinate when the disease has not appeared for several years. But because the spores survive for such lengthy periods, the risk is always present.
Anthrax is a disease listed in the World Organisation for Animal Health (OIE) Terrestrial Animal Health Code, 2011, (Article 1.2.3) and must be reported to the OIE (Chapter 1.1.2 – Notification of Diseases and Epidemiological Information).